A new flavor is brewing in the world of craft liquors as distillers borrow from the beer world and add hops for an aromatic twist.

Recent products include hopped whiskies such as R5 from Charbay Artisan Distillery & Winery in the Napa Valley and Hopmonster from the Corsair Distillery with operations in Tennessee and Kentucky. Other examples include Hatter Royale from New Holland Brewing Co. in Michigan and Hopskey from Square One Brewery in St. Louis. In the non-whiskey category there’s Hophead Vodka from Anchor Distilling Co. in San Francisco and a hopped gin from the New York Distilling Co. Beyond the hard stuff, there’s even a half-dozen or so hopped hard ciders.

The move, says H. Joseph Ehrmann, who carries several of the hop-flavored liquors at his Elixir bar in San Francisco, is inspired by the desire to stand out. “They’re up against the big boys, the big brands and they’re trying to make something that’s going to compete and be unique so that people aren’t looking at them as another bourbon or another American single malt.”

It also tracks the boom in India pale ales — the hoppy beers beloved by craft beer enthusiasts — as well as the quest for innovative cocktails.

Industry-wide, there’s been an explosion of flavored spirits in the past few years, especially the many shades of vodka, driven by efforts to attract new customers and expand shelf space. But Christopher Null, who blogs about liquor at Drinkhacker.com, sees the hop-flavored spirits trend as less about growing market share and more about craft distillers getting in “mad scientist” mode, exploring the limits of what’s possible.

Allen Katz, co-founder of New York Distilling, laughs at the mad scientist label, but concedes there’s may be some truth to it. “We’re just trying to have fun. We are trying to be purposefully different, not esoteric.”

The Brooklyn distillery’s Chief Gowanus New-Netherlands Gin harks back to the days of early Dutch immigrants who were looking to recreate genever using readily available ingredients. In their case, it was rye. In this case, an unaged, double-distilled rye whiskey is put back in a traditional pot still with juniper and a small amount of cluster hops, distilled again, then finished off with three months in a barrel previously used to age rye.

“We’re trying to offer something that in our case has a historical context, which we like, but that most people have never experienced before,” says Katz.

Aromatic and assertive, hop-flavored liquors aren’t for everyone, but they play well with people who are interested in the craft distilling scene and in trying new things, says Ehrmann. “It’s kind of like smoke or spice; you don’t get a huge amount of people who like it right off the bat.”

Anchor Distilling Co. president David King says there are two types of people who like Hophead Vodka, “the really quite serious craft mixologists like it because it’s so unusual and the craft beer guys like it.”

Though it’s definitely a niche market, sales have been steady, with 4,000 9-liter cases sold in the past 18 months, says King. “It’s an acquired taste, but the people that acquire it like it very much.”

King was literally led by the nose to the trend when he walked into the hop room of sister company Anchor Brewing and was struck by the rich, funky smell.

“Have you tried distilling this?” he asked, and Hophead was born.

Hop-flavored liquors are made in various ways, but the whiskies generally get their flavor by being distilled from consumer-ready, hoppy beers, as opposed to the much cheaper regular whiskey mashes.

Charbay’s R5 Lot No. 3, the current release, is distilled from Bear Republic Brewery’s Racer 5 IPA beer and it takes 10 gallons of beer to make a gallon of whiskey, which is further reduced by the 3 percent “angel’s share” lost during barrel aging, says Susan Karakasevic, co-owner and general manager of Charbay. The process shows up in the price, around $80 a bottle.

Charbay’s venture into hop-flavored whisky dates back to 1999, when the father-son team of Miles (Susan’s husband) and Marko Karakasevic became intrigued by the idea of distilling bottle-ready beer. The first distillation used 20,000 gallons of Pilsner to create 1,000 gallons of whiskey.

Charbay chose to release the ‘99 distillation in lots so customers could experience its aging. They’re currently on Release III, which totaled 10 barrels ($450 a bottle) and have a waiting list for Release IV, which will be just eight cases.

Null has tried the R5 and liked it. “It really has that punchy herbal and pine tree character to it you just don’t get in whiskey,” he says.